I'm a peon at a university, and I would say the rule is reversed there for most people. Everyone has things they have to do, but getting them done takes no more than 20% of the time. The rest of the time you are supposed to be doing your own thing: your research, your grant writing, etc. For faculty, that's the whole point. For some of the staff, like me and I guess the guy in the previous comment, there's this twilight zone where you are not sure if you're supposed to be doing something on your own initiative or just standing by for when you are needed. Of course, some of the staff are expected to always be busy with not-their-own-thing. If there is "overemployed-by-regulation" it's because of an essential trust that people working there are already motivated to pursue their own interests which are also the interests of the university. Sure, there are slackers, but it's better to have a creative culture that allows that than to stifle both the slack and the creativity.

When you're hired at Google, you only have to do the job you were hired for 80% of the time. The other 20% of the time, you can work on whatever you like – provided it advances Google in some way. At least, that's the theory. Google's 20 percent time policy is well known in software engineeri...